basement reno advice

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21 year old house with 2 original furnaces (1 for 2nd floor, 1 for main and basement). Basement is currently unfinished, and i want to cover the ducting in. I've heard new furnaces (possibly brand new A/C installed also) need to be reducted -- is this always the case? I don't want to be ripping out wallboard and studwalls becuase of poor planning.

Along the same line of thought, is it a "big deal" to have the installer move new furnaces 5 feet in one direction from the old location to accomodate the room set up ie is it alot more time and money than its worth?

thanks for any info you can provide.

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